Thee consortium GeoTrAc[1]-AASPE[2]-GEOPS[3]-LMC14[4] acquired an automated dosing system with funding from the DIM Matériaux anciens et patrimoniaux, PANOPLY and the own funds of the 4 teams involved.
14C geochronology, whether intended to constrain carbon cycles in our current environment or to clarify the chronological frameworks of palaeoclimatic, archaeological and museum studies, requires numerous measurements of reference products in addition to those of the sample selected in order to guarantee the quality of the analyses.
The aim of these peripheral measurements is to ensure accurate, reproducible and precise dating of the sample. They are all the more important when the sample is small and therefore sensitive to even the slightest contamination. These analyses consist of measuring high-value ‘blanks’ and reference materials for the physical measurement, and ‘blanks’ and reference materials of known age for the complete analysis chain (chemistry, transformation into CO2 and/or graphite, measurement). These reference products account for 40% of the measurements carried out on ECHoMICADAS and their weighing represents 1 to 2 hours of weighing per day.
Today, solutions exist to simplify this laborious task of weighing. Automatic balances allow simplified, rapid and accurate weighing of our reference materials and iron in specific containers. The LSCE has equipped itself with such an instrument, which will save time and enable us to develop the even more individualised chemistry required for ever-smaller samples.
This automatic weighing system is fitted with a precision balance, equipped with a hopper-weighing head that allows micro-quantities of material to fall into a container placed on the balance pan, and a control system that regulates the falling speed and the quantity of material falling until the set point is reached. The weighing heads, which are specific to each material, are fitted with an electronic chip that enables the specific use of the hopper to be preserved according to the mechanical properties (grain size, density) of the material to be weighed (learning).
Financing : DIM Matériaux anciens et patrimoniaux, PANOPLY, equity capital of the 4 co-sponsoring groups
[1] GeoTrAc: équipe Géochronologie, Traceurs et Archéométrie du LSCE, Laboratoire des Sciences du Climat et de l’Environnement – UMR CEA CNRS UVSQ
[2] AASPE: Archéolozoologie et Archéobotanique: Société, Pratiques et Environnements – UMR 7209 CNRS MNHN
[3] GEOPS: Géosciences Paris Saclay – UMR Université Paris-Saclay CNRS
[4] LMC14 : Laboratoire de Mesure du 14C – UMS CEA CNRS IRSN MCC IRD, rattachée au LSCE
